Stop mechanism



June 25, 1963 B. JUNGE ETAL 3,094,883

Q STOP MECHANISM Filed June 30, 1961 INVENT KENNETH C. BRO BY BJARNE JUNGE i i ATTORNEY 3,694,883 STOP MECHANISM Bjarne Juuge, San Jose, and Kenneth C. Brown, Santa (Ilara, Calif., assignors to International Business Machines Corporation, New York, N.Y., a corporation of New York Filed June 30, 1961, fier. No. 12l,39 Claims. (6i. 74527) This invention relates to an improved stop mechanism or brake, sometimes referred to as a detent mechanism. In the usual positioning device, wherein one member must be positioned to one of a number of selected positions as respects another member, one means for insuring that the two members are located accurately with respect to each other at a selected position is by means of a detent. In such an arrangement, a tooth, dog or pin, for example, can be inserted into a hole or notch cooperating therewith. In this type of an arrangement, the time required to withdraw the tooth or pin is comparable to the time required to insert the pin. This withdrawal time therefore operates to limit the speed with which the movable member can be positioned to another or subsequent position. Accordingly, it is an object of the present invention to provide a detent or stop means wherein the time required to release a member movable with respect to another is substantially divorced from the time required to effect detenting or locking of the two together.

Insertion of a detent into a cooperating hole or slot calls for motion in one direction whereas releasing or unlocking the two members with respect to each other calls for motion in an opposite direction. Thus, a twodirectional drive such as provided by a solenoid is required to effect this function. However, there is usually a practical limit to how much power can be developed by a solenoid and since the insertion of a detent ordinarily can be expected to provide some small or fine positioning movement of the members, it becomes another object of this invention to provide a detenting means which is driven in a single direction for both locking and unlocking two relatively movable members and which can develop considerable force to provide fine positioning of significantly large masses.

A feature of the present invention is that in a relatively limited space, a detent means is provided having the cam action of a very long and tapered plunger.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a perspective view of one embodiment of the invention.

FIG. 2 shows another embodiment of the invention, and viewed end-on as related to the invention of FIG. 1.

FIG. 3 shows another embodiment of the invention and also viewed end-on as related to the invention of FIG. 1.

Briefly stated, according to the invention, as shown in FIG. I, lock or stop member is welded on a shaft 12. Shaft 12 is driven by a motor 12a supported on a fixed member or frame 12b. Lock member 10 is formed with a gap or relieved segment \14 extending from surface 16 to surface v1'8. It is to be noted that surface 16 is narrower than surface 18. The thickness of member 10 increases from surface 16 counterclockwise (as viewed from the left in FIG. 1) around to some predetermined position such as that defined by line 20 whereupon the thickness becomes uniform to provide a dwell portion 19. The counterclockwise arcuate distance from the edge of LCQ surface 16 to surface 18 provides a pair of face cams 17a and 17b each including a ramp portion 15 around to line 20' and a dwell portion 19 from line 20 to the edge of surface 18. Thus, face cams 17a and 17b are provided on opposite sides of member 10.

A movable member or rack 22 displaceable left and right, as viewed in FIG. 1, is arranged to support a number of rollers 24 mounted upright on spindles to serve as teeth in the rack 22. The spacing between adjacent rollers 24 is such as to accommodate the complete passage therethrough of the maximum thickness of lock member 10. Thus, member 10 can rotate 360 through the interstice between any two adjacent rollers 24 or teeth.

In the foregoing description, the term stubs is to be understood to include the teeth of a rack, as well as rollers 24 or any fixed projecting members analogous. thereto.

In operation, clockwise rotation of shaft 12 a small amount from the position shown will position the longitudinal slot or gap 14 to permit rollers 24 to pass therethrough thereby releasing rack 22. Rack 22 can then be moved by any suitable means for coarse positioning. After coarse positioning of member 22 to locate a selected interstice roughly adjacent lock member 10, shaft 12 is further rotated clockwise interposing surface 16 between a selected pair of adjacent rollers 24 with considerable clearance. Assuming that member 22 is not accurately located at the desired ultimate station with respect to the frame member supporting shaft 12, the rotation of shaft 12 will cause either face cam 17a or 17b to cam the rack 22 into its final position and be locked firmly thereat when dwell portion 19 has been rotated into position between the selected rollers 24. Release of member 22 for movement with respect to the fixed frame member 12b will, as noted above, be effected by a further limited rotation of member 10 a few degrees in the same direction.

Referring to FIG. 2, there is shown a variation on the above arrangement wherein three racks of rollers 24 have been provided to cooperate with a single rotary cam member so that two of the three racks will be held fixed, i.e. detented while a third member is released. In FIG. 2, rack 22 is shown and as viewed therein moves toward and away from the viewer. A shaft 12' is provided upon which is mounted a cam member 10 having a pair of face cam surfaces 17' corresponding to cam surfaces 17a and 17b in FIG. 1 but more limited in the degree to which the ramp portion 15' and dwell portion 19' extend around member It). In FIG. 2 line 20' defines the end of the ramp surface 15 and counterclockwise beyond line 20 it is understood that earn 10' is of uniform thickness to provide a dwell portion 19' to cam surface 17.

FIG. 3 is somewhat similar to FIG. 2 and utilizes the arrangement of FIG. 1 to either lock or release simultaneously a plurality of racks 22". The reference numerals in FIG. 3 have been followed by double prime marks to designate components corresponding to those in FIGS. 1 and 2.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in the form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A stop mechanism for arresting a rack of spaced stubs wherein said rack moves relative to another member, said stop mechanism comprising a shaft supported by said other member, means for rotating said shaft in a predetermined direction, a stop member mounted on said shaft for rotation therewith, said stop member being formed to include a face cam surface on at least one side of a plane oriented substantially normal to the direction of relative movement between said rack and said other member, said face cam surface being further arranged to be interposed between a'pair of said stubs, the maximum thickness of said stop member being passable between any pair of adjacent ones of said stubs, said cam surface being interrupted by a sufficiently relieved portion to pass said rack of stubs therethrough when aligned therewith whereby rotation of said stop member in one direction interposes said cam surface between adjacent stubs of said rack, moves said rack with respect to said other member in accordance with said cam surface, and releases said rack under continued rotation of said stop member in the same direction upon alignment of said relieved portion with said stubs.

2. A stop mechanism for arresting a pack of spaced stubs wherein said rack moves relative to another member, said stop mechanism comprising a shaft supported by said other member, means for rotating said shaft in a predetermined direction, Ia stop member mounted on said shaft for rotation therewith, said stop member being formed to include a pair of face cam surfaces arranged in back-to-back relation on opposite sides of a common plane, said common plane being oriented substantially normal to the direction of relative movement between said rack and said other member, said face cam surfaces being further arranged to be interposed between a pair of said stubs, the maximum thickness of said stop member between said surfaces being passable between any pair of adjacent ones of said stubs, said cam surfaces being interrupted by a sufficiently relieved portion to pass said rack of stub-s therethrough when aligned therewith whereby rotation of said stop member in one direct-ion interposes said face cam surfaces between adjacent stubs of said rack, moves said rack with respect to said other member in accordance with said cam surfaces, and releases said rack under continued rotation of said stop member in the same direction upon alignment of said relieved portion with said stubs.

3. The invention according to claim 2 wherein the spacing between said cam surfaces is uniform over a terminal portion thereof to provide a dwell portion thereto for detenting said rack.

4. A stop mechanism supported by a frame member, said stop mechanism comprising a plurality of racks each having a series of stubs, each said rack constructed to move relative to said frame member and relative to each other to position the interstice existing between an adjacent pair of said stubs on each said rack substantially into a common plane disposed normal to the direction of movement of said racks with respect to said frame member, a shaft, a stop member common to all said racks and mounted on said shaft for rotation therewith, the sides of said stopmember being formed to include a face cam surface on at least one side of said plane, the periphery of said stop member being spaced from said shaft in said plane sufficiently to be interposed between selected pairs of adjacent stubs on each of said racks, the interstice between said adjacent stubs being great enough to pass the maximum thickness of said stop member therethrough under continuous rotation of said shaft, said periphery being interrupted by a portion sufficiently relieved to pass the stubs of any one of said racks when aligned therewith, whereby rotation of said stopmember to align said relieved portion with the stubs of one of said racks releases the latter for movement with respect to said frame member while holding the balance of said racks with respect thereto.

' 5. A stop mechanism supported by a frame member, said step mechanism comprising a plurality of racks each having a series of stubs, each said rack constructed to move relative to said frame member and relative to each other to position the interstice existing between an adjacent pair of said stubs on each said rack substantially into a common plane disposed normal to the direction of movement of said racks with respect to said frame member, a shaft, a stop member common to all said racks and mounted on said shaft for rotation therewith, the sides of said stop member being formed to include a face cam surface on at least one side of said plane, the periphery of said stop member being spaced from said shaft in said plane sufliciently to be interposed between selected pairs of adjacent stubs on each of said racks, the interstice between said adjacent stubs being great enough to pass the maximum thickness of said stop member therethrough under continuous rotation of said shaft, said periphery being interrupted by a plurality of portions sufiiciently relieved to pass any one of said racks when aligned therewith, said relieved portions being arcuately displaced with respect to each other to substantially simultaneously release said racks for movement with respect to said frame member when said portions are aligned with the stubs of said rack.

No references cited. 

1. A STOP MECHANISM FOR ARRESTING A RACK OF SPACED STUBS WHEREIN SAID RACK MOVES RELATIVE TO ANOTHER MEMBER, SAID STOP MECHANISM COMPRISING A SHAFT SUPPORTED BY SAID OTHER MEMBER, MEANS FOR ROTATING SAID SHAFT IN A PREDETERMINED DIRECTION, A STOP MEMBER MOUNTED ON SAID SHAFT FOR ROTATION THEREWITH, SAID STOP MEMBER BEING FORMED TO INCLUDE A FACE CAM SURFACE ON AT LEAST ONE SIDE OF A PLANE ORIENTED SUBSTANTIALLY NORMAL TO THE DIRECTION OF RELATIVE MOVEMENT BETWEEN SAID RACK AND SAID OTHER MEMBER, SAID FACE CAM SURFACE BEING FURTHER ARRANGED TO BE INTERPOSED BETWEEN A PAIR OF SAID STUBS, THE MAXIMUM THICKNESS OF SAID STOP MEMBER BEING PASSABLE BETWEEN ANY PAIR OF ADJACENT ONES OF SAID STUBS, SAID CAM SURFACE BEING INTERRUPTED BY A SUFFICIENTLY RELIEVED PORTION TO PASS SAID RACK OF STUBS THERETHROUGH WHEN ALIGNED THEREWITH WHEREBY ROTATION OF SAID STOP MEMBER IN ONE DIRECTION INTERPOSES SAID CAM SURFACE BETWEEN ADJACENT STUBS OF SAID RACK, MOVES SAID RACK WITH RESPECT TO SAID OTHER MEMBER IN ACCORDANCE WITH SAID CAM SURFACE, AND RELEASES SAID RACK UNDER CONTINUED ROTATION OF SAID STOP MEMBER IN THE SAME DIRECTION UPON ALIGNMENT OF SAID RELIEVED PORTION WITH SAID STUBS. 